The invention relates to a blade for a stripping and peeling tool for stripping and peeling a pre-insulated pipe, including a main body, wherein the main body is configured as an elongate thin plate, wherein the plate is configured so as to be convex and the apex of the convex curvature extends along the length of the plate, wherein a cutting edge is disposed on a longitudinal edge of the plate, or of the main body, respectively, said cutting edge serving for releasing the insulation layer from an internal pipe, and an insert blade.
Peeling apparatuses for external shell faces of pipes so as to peel off the external oxidized layers in order for optimum welded connections to a fitting to be able to be carried out are mainly known from the prior art. In order for the welded connection to withstand the necessary requirements, and since the latter are achievable only when the external shell face does not have any contaminations and any oxide layer, it is important for the outermost layer to be removed. JP 6-79501 discloses such a peeling tool for peeling off the external shell face of a pipe.
Stripping apparatuses for stripping a metal pipe that is provided with a protective layer are also known from the prior art. EP 1 118 405 A1 discloses such an apparatus.
However, both devices mentioned above are not suitable for stripping and peeling a pre-insulated pipe which typically includes a somewhat thicker foam insulation which has to be separated from the internal pipe, and the external shell pipe face of the internal pipe subsequently has to be reworked in such a manner that the surface is suitable for welding. Such pre-insulated pipelines are used where a positive insulation of the medium in relation to the environmental conditions is required, for example for conveying coolant media in cooling systems. An insulation layer, preferably from foamed plastics material, is disposed about the medium-conveying internal pipe, or the medium pipe, preferably from plastics material, wherein the insulation layer is surrounded by an external skin or an external pipe which are preferably formed from plastics material or else from a metal and serve as protection of the insulation layer. Such pipelines at the ends thereof have to be stripped, and the medium pipe has to be peeled on the external shell face so as to be able to be connected to fittings or further pipes, since the connection by way of the medium pipe is performed so as to guarantee the tightness.
EP 3 213 890 A1 discloses a tool by way of which stripping and peeling a pre-insulated pipe is possible. The blade used enables both stripping by separating the insulation layer, as well as peeling the external shell face of the internal pipe. However, it is disadvantageous in the embodiment mentioned above that the blade, or the cutting edges disposed thereon, respectively, are rigidly aligned and cannot adapt to the external shell face of the internal pipe.
It is an aspect of the invention to propose a blade which is suitable for stripping and peeling pre-insulated pipe ends and guarantees optimal peeling of the external shell face, and enables an optimal process in terms of economy by way of which the procedure can be carried out in an efficient manner.
This aspect is achieved according to the invention in that the insert blade is configured as a separate part and the blade includes an axle, wherein the axle serves for mounting the insert blade in the main body and preferably protrudes through the insert blade, wherein the insert blade has a cutting edge and the insert blade is disposed in the main body in such a manner that the cutting edge of the insert blade runs parallel to the cutting blade on the main body.
The blade according to the invention for stripping and peeling a pre-insulated pipe includes an main body, wherein the main body is configured as an elongate thin plate. The plate across the complete length has a convex design embodiment, that is to say that the plate on the internal side thereof which is directed toward the internal pipe, as also on the external side, has a curvature, preferably on a radius, wherein the two curvatures, preferably radii, preferably run so as to be concentric. On account of the convex design embodiment of the plate, the apex of the curvature, preferably radius, extends along the length of the plate, or of the main body, respectively. A cutting blade is disposed on the longitudinal edge of the main body, or of the plate, respectively, wherein the cutting blade serves for releasing the insulation layer from the internal pipe. In order for the insulation layer to be released, the blade is rotated to the one side, or in the one rotation direction, respectively, and subsequent peeling is preferably carried out by means of a rotation in the opposite direction, wherein peeling can also be performed during the rotation or the release of the insulation layer, respectively.
The blade includes an insert blade which is configured as a separate part and is disposed in the main body. The insert blade by means of an axle which protrudes through the insert blade is mounted in the main body, on account of which the insert blade has the possibility of moving upwards and downwards and is guided on the left and the right of the main body.
The cutting edge that is disposed on the insert blade is aligned so as to be parallel to the cutting edge on the main body, wherein said insert blade is aligned in the opposite direction of the same direction as the cutting edge on the main body. On account of the mutually opposing, or opposite alignment, respectively, of the two cutting edges it is achieved that the release of the insulation layer from the internal pipe is performed while the blade is being driven inwards in the one rotation direction, that is to say in or counter to the clockwise direction, and the subsequent peeling is then performed while the blade is driven outwards and in the opposite rotation direction. However, when the cutting edges on the blade, or on the main body, respectively, and on the insert blade are aligned in the same direction, the peeling of the internal pipe is performed during the release of the insulation layer, thus also while the blade is driven inwards. On account thereof, unnecessary movement procedures during the process can be avoided in both cases, on account of which the procedure can be carried out in an efficient manner.
The main body preferably has a recess in which the insert blade is disposed. The insert blade is guided and aligned in an optimal manner on account of the insert blade being disposed in the recess.
It is advantageous that the recess in the main body is configured so as to be continuous and is completely enclosed by the main body. This means that the recess completely penetrates the main body, or the plate, respectively, and is surrounded by the main body on all sides such that the main body frames the recess. This is associated with the advantage that the main body is inherently stable and does not have any protrusions or corners which project separately and catch on the insulation layer.
According to one preferred embodiment the blade has a spring element which serves for pressing on the insert blade. Since the insert blade is mounted on the axle, the insert blade has the possibility of moving downwards and upwards so as to adapt to the external shell face of the internal pipe. In order to now exert a certain pre-tensioning on the insert blade, or so as to achieve a force for peeling the external shell face, respectively, the spring element presses the insert blade downwards, or against the internal pipe, respectively. The insulation layer which runs above the blade likewise exerts a contact pressure force on the blade, said contact pressure force serving the peeling procedure.
The invention is also distinguished in that the main body has a thickness of only 1 to 4 mm, particularly preferably of 1.5 to 3 mm; the piercing of the insulation layer is enabled on account thereof. It is moreover advantageous when the main body on the two longitudinal sides and preferably on the end side has an incline. The inclines on the longitudinal sides enable the insulation to better slide across the blade, and the incline on the end side minimize the resistance when piercing the insulation layer.
It has proven advantageous when the cutting edge on the main body extends across the complete length of the main body; this enables the insulation layer to be separated from the internal pipe in a simple manner.
The insert blade preferably has a gradation of the thickness, or of dissimilar heights, respectively, across the length of the insert blade. The internal face of the insert blade faces the internal pipe to be peeled and has dissimilar heights. This serves for the cutting blade coming into contact with the external shell face even when the rear region, or the clearance region, respectively, of the insert blade in the peeling procedure at first runs across the as yet unpeeled external shell face which has an even larger diameter than the finally peeled diameter. It is ensured on account of the height differentials that the cutting edge, or the peeling region, respectively, of the insert blade nevertheless can engage in the shell face to a sufficient depth so as to subtract material, since the cutting edge is configured so as to be higher than the rear region of the blade, said rear region serving as the clearance region and bearing on the external shell face only once deeper peeling is no longer desired. The peeling region preferably protrudes beyond the clearance region by between 0.2 to 0.8 mm, particularly preferably 0.2 to 0.5 mm in terms of the height on the internal face of the insert blade.